Pneumatic tires in use typically collect mud and dirt on the sidewall, as well as the lettering on the tire. This results in an unsightly tire. The purpose of the present invention is to reduce the amount of dirt which adheres to the sidewall and lettering by including in a rubber compound a pretreated a silica with a fluorinated silane. The presence of the silica pretreated with a fluorinated silane provides an automatic cleaning effect decreasing the need for scrubbing the sidewall.
Pneumatic tires also collect water in the tread grooves. The purpose of the present invention is also to reduce the adhesion of water and mud inside the grooves, through the presence of the silica pretreated with fluorinated silane in the rubber tread compound, thus obtaining a better evacuation of water as well as a self-cleaning effect.
A clean and dry tire also reduces the weight of the tires as well as the air resistance, thus reducing the fuel consumption. Efforts to reduce air resistance of objects in motion in order to achieve a reduction in fuel consumption have been disclosed for surfaces such as the metallic surface of an airplane.
Against this background, it is an object of the present invention to provide rubber tires that have an improved dirt-repellence whereby the weight of the tire and, consequently the air resistance, are reduced and savings in fuel consumption are obtained.
It is another object of the invention to provide tires having a self-cleaning effect and permitting a reduction of cleaning material to be used.